There are over half a million chronic kidney disease (CKD) patients in the United States, with over 100,000 new CKD patients each year. There is a four percent annual increase in projected prevalence population due to such driving factors as, for example, high blood pressure, diabetes, and an aging population.
Hemodialysis is the treatment of choice for 92% of CKD patients, because without hemodialysis or some other form of treatment those CKD patients would die. A typical CKD patient undergoing hemodialysis treatment must have his or her vascular system connected to a hemodialysis machine two to three times per week. For hemodialysis, there are three common vascular access site options. The preferred access site option is an arteriovenous fistula (AVF), which is a direct, surgically created connection between an artery and a vein, preferably in the wrist, or alternatively, in the forearm, upper arm, leg, or groin. Another access site option is an arteriovenous graft (AVG), which is a surgically created connection between an artery and vein using an interposed synthetic conduit. The final major access site option is a catheter inserted into a large vein in the neck, chest, leg, or other anatomic location.
Patients with an AVF have less morbidity, less mortality, and a lower cost of care compared with patients with an AVG or a catheter; therefore, an AVF in the wrist is the preferred form of vascular access for hemodialysis. Patients with an AVG or catheter have substantially higher rates of infection and death than patients having an AVF, with catheter patients having the worst outcomes. In addition, patients having an AVG or catheter have a higher average cost of care, with catheter patients having the highest costs. If a patient is eligible for an AVF, the wrist or forearm is generally preferred over an AVF in the upper arm due to higher rates of hand ischemia and the generally shorter and deeper vein segments of the upper arm.
Unfortunately, about 85 percent of patients are ineligible for an AVF in the wrist, mostly due to vein and artery diameters that are too small. Furthermore, about 60 percent of all AVFs created are not useable without additional surgical and interventional procedures due to an occurrence commonly referred to as “maturation failure,” which is correlated with small vein and artery diameter. The availability of veins and arteries with larger diameters is correlated with higher AVF eligibility and lower rates of maturation failure.
Currently, there are few options for permanently and persistently increasing the diameter of a vein or artery. All current methods use mechanical methods of dilation, such as balloon angioplasty, that can lead to vein or artery injury. Since a patient needs to have peripheral veins and arteries of a certain size for a physician to create an AVF, it is desirable to have a method and system for persistently and permanently increasing the size or diameter of peripheral veins or arteries.
Approximately 7 million people in the US suffer from chronic venous insufficiency and hypertension, which can progress to venous ulceration. Lower extremity ulcer is the most common form of chronic wound, with an estimated prevalence of 1% of the US population. About 2.5 million people in the US have a lower extremity ulceration and about 600,000 people seek treatment for a venous ulceration of the lower extremity each year in the US. The incidence of venous ulceration is expected to rise as the population ages.
In a survey of patients with venous ulcers, 81% of patients reported an adverse effect on mobility, 56% reported spending up to 8 hours per week on ulcer care, 68% reported a negative emotional impact, including fear, social isolation, anger, depression, and negative self-image. In the survey, 80% of patients are not working outside the home; and of the 20% employed, leg ulceration correlated with time lost from work, job loss, and adverse effects on finances.
Lower extremity venous hypertension and ulceration is costly to treat and places a substantial burden on health care providers and systems. In a study of 78 venous ulcer patients at the Cleveland Clinic, median ulcer size was 2.8 cm2 (mean=9.4 cm2) and 5% had bilateral ulcers. The median time to ulcer healing was 77 days (mean=108 days) and the mean cost of treatment was $2,400 per month. The mean total cost of treatment to heal an ulcer was $9,685 per patient. For patients requiring more than a year to heal, the average total cost per patient was $18,534.
In a majority of cases, venous hypertension and ulceration results from valvular incompetence secondary to deep vein thrombosis or an unknown cause. In a substantial minority of cases, venous hypertension and ulceration results from femoral or pelvic venous obstruction secondary to deep vein thrombosis, vein injury, or extrinsic vein compression. Chronic tissue exposure to localized venous hypertension leads to dilation of capillaries with increased permeability and leakage of plasma and erythrocytes, trapping, activation of leukocytes in the microcirculation, and the release of free radicals and other toxic products, such as tumor necrosis factors and collagenase, which can promote cell death and tissue damage. Leakage of fibrinogen into surrounding tissues binds or “traps” growth factors and cytokines, and renders them unavailable for maintenance and repair of tissue integrity.
Lower extremity venous hypertension presents clinically as leg redness, swelling, pain, edema, pruritus, scaling, discharge, and lipodermatosclerosis. Ulcers generally develop on the medial aspect of the leg and possess irregular borders and can be associated with severe pain. Venous ulcers are often complicated by superimposed bacterial infection. The arterial circulation is usually adequate. Current treatments for lower extremity venous hypertension and ulcer are often inadequate. Patients are mostly offered palliative treatments, with the goal of healing ulcers and preventing recurrence, including aggressive wound care, compression therapy to decrease lower extremity venous pressure and increase venous return, lower extremity vein stripping or ablation, and skin grafting. However, current treatments often fail to heal ulcers and recurrence rates for healed ulcers are high.
Currently, small “heart pumps” exist; however, such pumps are costly and not designed and dimensioned for use in an extremity or for the uses described herein. As such, there is a need in the art for systems, components, methods, and pump devices that can increase the diameter of peripheral veins and arteries at a reasonable cost. Additionally, there is a need for a systems, components, methods, and pump devices that can increase lower extremity venous return, reduce lower extremity venous hypertension, and heal venous ulcers.